get all sequencer strips in python
Hey thanks to batfinger and cmomoney, here's the answer :

### Strips ###
for scene in bpy.data.scenes: 

    if scene.sequence_editor is not None:

        strip = scene.sequence_editor.sequences_all

        if strip is not None:


works perfectly to get all the strip in the sequencer editor in any scene of your blend file ! hope it'll help for people in same situation !